Insignia tv powers off at random - Videokarma.org TV - Video

Sealtest · #1 09-04-2020, 02:38 AM

Model number : NS-LCD32-09

Hey all, I haven't been on this forum in quite a while but I used to tinker with CRT tv's quite a bit until repairing quite a collection and then being stuck with them, which wasn't cash money.

Anyways, I do understand that most flat panel sets aren't worth fixing and are easily totaled out, but I was hoping for a common issue with these sets I can look into.

The issue I have with this set is that it powers off at random with no warning. Sometimes it works for a good while, then won't stay on for more than a few minutes. The problem is at random and I can't make the set purposely act up.I did remove the controls to see how that would work, but with no luck. Funny thing too is my aunt called me a few months ago with the same brand set with the same issue, and after telling her to do the same thing she said it started to work, then recently told me it is doing the same thing. So this is for both of us now, and more personal. I don't know the model of her set though. My set did just stay on for maybe 30 mins without anything connected.

I have repaired hifi stereo equipment for years and have the knowledge to do repairs, but have no idea where to start on this. When I work on a stereo unit, lets say a pioneer sx-780, I have a schematic and a treasure trove of online repair documentation with common issues. With flat panel sets I never can find any of this.

Any help would be great. I understand it may not be worth fixing but I have the time to work with it and learn overall. Worst case it'll go back to the dumpster it came from.

Electronic M · #2 09-04-2020, 10:57 AM

If you have one of those Chinese ESR/RLC/transistor testers I'd recommend checking all the lytics. It's possible they are marginal and causing shutdown.

Sealtest · #3 09-04-2020, 01:12 PM

Quote:

Originally Posted by Electronic M

If you have one of those Chinese ESR/RLC/transistor testers I'd recommend checking all the lytics. It's possible they are marginal and causing shutdown.

I do have a pretty good Chinese cap tester I have compared with my heathkit it28. I can certainly give that a shot.

I know with some sets I've had I could look up my issue, and someone would direct me to the exact cap that was a known issue which always helped. Seems like with this model I'm out of luck.

I did refolw all of the larger components on the power supply. I get almost exact voltages from every pin but on the main board (bottom left connector that deals with the controls), I have a 5v pin reading at 3.32V. I'm unsure if I should be looking on the power supply or on the mainboard, or if that's an issue.

I just hate intermittent issues. Sometimes it seems it would be better if the units just 100% broke. It's like that when I'm working on cars and stereo gear though, so it may be different here.

I have also tried running the set without the back and with a fan blowing on it, with no change I have noticed. Currently there are no inputs connected to the set but it did still mess up when there were.

Electronic M · #4 09-04-2020, 01:51 PM

Quote:

Originally Posted by Sealtest

I do have a pretty good Chinese cap tester I have compared with my heathkit it28. I can certainly give that a shot.

I know with some sets I've had I could look up my issue, and someone would direct me to the exact cap that was a known issue which always helped. Seems like with this model I'm out of luck.

I did refolw all of the larger components on the power supply. I get almost exact voltages from every pin but on the main board (bottom left connector that deals with the controls), I have a 5v pin reading at 3.32V. I'm unsure if I should be looking on the power supply or on the mainboard, or if that's an issue.

I just hate intermittent issues. Sometimes it seems it would be better if the units just 100% broke. It's like that when I'm working on cars and stereo gear though, so it may be different here.

I have also tried running the set without the back and with a fan blowing on it, with no change I have noticed. Currently there are no inputs connected to the set but it did still mess up when there were.

Don't give up on more precise help just yet. Your post isn't even a day old, and I have only worked on a couple of LCD sets...(I tend to view anything without vacuum tubes in it as disposable junk and don't often bother to try fixing it).

Sealtest · #5 09-07-2020, 12:16 AM

Quote:

Originally Posted by Electronic M

Don't give up on more precise help just yet. Your post isn't even a day old, and I have only worked on a couple of LCD sets...(I tend to view anything without vacuum tubes in it as disposable junk and don't often bother to try fixing it).

I went ahead and ordered a replacement mainboard listed online as "working", so we shall see.

I understand what you mean though. I used to work on CRT solid state sets some with pretty good success. I cleaned out a few tv repair shops and got all sorts of schematics, casefiles, tools, etc and went pretty hard for a while on repairing sets. Those things I mostly understood but my experience was mostly in vintage audio repair. All parts are through-hole and nice and easy to work on..

All tube chassis are another story. I have a mint condition 1955 RCA floor tv in a metal cabinet, and a rough Admiral from 1953. Those I would recap, test tubes, take measurements, with no luck. One of these days I will have to get on those again. I cleaned out a repair shop and got some extension cables to keep the CRT connected to the chassis for adjustments. I have the tools but have the TV's stored with family.

At least with flat panel sets I can take them back to the dumpster they came from.

I'll update when I get the new board for this set, and go from there.